Shockproof watch bearing retainer



Nov. 29, 1949 J. WlDMER-STEINER SHOCKPROOF WATCH BEARING RETAINER FiledMay 7, 1946 ATTORE EY Patented Nov. 29, 1949 UNITED STATES PATENT OFFICESHOCKPROOF WATCH BEARING RETAINER Jean Widmer-Steiner, Granges,Switzerland Application May '7, 1946, Serial No. 667,942 In SwitzerlandMay 2, 1945 2 Claims. 1

This invention relates to resilient retainers for watch bearings andmore particularly for the cap jewels of bearings for the balance staffsof watches and has for its object to provide a new and useful resilientretainer which will be efiicient in action and simple in construction.

The accompanying drawing shows, by way of example, a shockproof balancestaff bearing embodying the invention.

Fig. 1 is a section along the axis of the balance staff.

Fig. 2 is a plan view.

Fig. 3 is a cross sectional view on line III-III of Fig. 2.

l designates the balance staff. 2 is a movable bush carrying a piercedjewel 3 and a counterpivot jewel 4, this assembly formin the bearing ofthe pivot l. The bush 2 rests loosely on a conical or a rounded surface5 provided on an annular member 6 forming the body of the bearing. Theupper part of said member 6 forms a ring 1 serving to hold a spring 8bearing against the outer face of the counter-pivot jewel 4.

The spring 8 is a flat spring having the general shape of a U. Each arm9 and 9' of this U terminates in an arcuate portion Ill and it, theseportions havin a common centre coinciding with the centre of thecounter-pivot jewel, through which centre the axis of symmetry of the Ualso passes. The arcuate portions it and iii are each extended by atransverse portion ll, ll. These two transverse portions it and H are inmutual alignment and are located on the diameter of the jewel 4 which isat right angles to the axis of symmetry of the U. Each transverseportion extends on one side of the arcuate portion.

The spring 8 is hingedly connected to the member 6 forming a support, bymeans of its medial transverse portion i2 connecting the arms 9 and 9.For this purpose, the bearing support is provided with two grooves 53and it which are parallel and symmetrical to a diameter and which allowthe said medial portion ii to be inserted in a recess of the part 5 inwhich it can pivot.

On the other hand, the spring is removably fixed to the part 5 at twodiametrically opposite points by the ends M and i l of the transverseportions and I 1 extending outwardly from the arcuate arms ill, it ofthe U being inserted under the ring 1, whereas the spring bears againstthe jewel 4 by means of the enlarged ends it and [5 of the transverseportions ii and H extendin inwardly from the arcuate arms l0, ID of theU. j

When it is required to take the bearing apart, it is necessary first ofall to disengage the spring 8. For this purpose it is only necessary topress the parts l5 and I5 towards one another with a spike or withpincers and disengage the parts l4 and I4 from under the ring I. It isthen possible to swing the spring about its part 12 in order todisengage it from the parts of the bearing. The spring can be replacedin position by efiecting the reverse operations.

The advantages offered by the device illustrated and described hereinare as follows:

Owing to the special shape of the spring 8, the drilled jewel 3 and thecounter-pivot jewel 4 may be of very large diameter, which allows ofperfect lubrication.

The spring bears against the cap jewel 4 by means of the two free endsl5 and i5, thereby ensuring considerable resilience.

The construction of the bearing is very simple, since the holding of thespring only requires the two grooves l3.

Furthermore, the bush 2 shown, which holds the cap jewel loosely,facilitates the cleaning of the bearing. Said bush being partlycylindrical does not escape from the pincers during cleaning.

For lubrication, it is only necessary to remove the bush and thecounter-pivot jewel from the bearing, then lubricate like an ordinarypart and replace the bush in position in the bearing; said bush afteroiling adheres to the counterpivot jewel and can thus be replaced inposition without difliculty. The fact that the jewels are of largediameter enables a large drop of oil to be placed on them which, when ashock occurs, prevents any tendency to spread and the oil can retain itsabsolute viscosity for a very lon time, thereby ensuring the adjustmentof the watch.

The spring, which is pressed at M and 4, acts with a bending stress fromI5 and i5 on the overhanging arm; on the other hand, owing to its shape,an additional bending occurs by torsion between [5 and I5 and between[5/15' through M up to l2, thereby permitting of the most judiciousdistribution of the strength relatively to the cross-section with amaximum strength at the points of action for a minimum bulk andcross-sectional area.

I claim:

1. A shockproof watch bearing retainer comprising in combination with anannular bearing body, a bush movably supported therein, a cap jewelloosely carried by said bush, a generally U- shaped flat spring havinstraight arms each terminating in an arcuate portion, said arcuateportions being concentric with respect to said cap jewel and providedwith a transverse extension, said two transverse extensions bein inmutual alignment on both sides of said arcuate portions along a diameterof said cap jewel which is perpendicular to the axis of symmetry of saidU-shaped spring, said spring being hingedly connected with said annularbearing body by the transverse medial bar connecting its arms, and meansfor removably securing said spring to said bearing body by the ends ofsaid transverse extensions, the inner ends of said transverse extensions resiliently bearing against the cap jewel.

2. A shockproof watch bearin retainer as claimed in claim 1 wherein theannular bearing body is formed with two parallel grooves to receive thestraight arm portions of the U-shaped spring and with a transverserecess connecting said grooves to receive the hinged transverse medialbar of said spring.

